Aircraft flying at a certain speed are equipped with retractable landing gear which can be manoeuvred between a deployed position and a retracted position in a bay of the aircraft, which is closed by doors. To that end, the doors are moved by a door actuator and retained in the closed position by one or more door hooks. Similarly, the landing gear is moved by a landing gear actuator and retained in the retracted position by a landing gear hook. The landing gear further comprises an unlocking actuator for unlocking it when it is locked in the deployed position and thus allowing it to be raised toward the retracted position.
The manoeuvre of deploying a landing gear generally comprises the following successive steps:
a. Pulling on the doors of the bay to relieve the door retaining hook;
b. Actuating the door hook or hooks to free the doors;
c. Opening the doors;
d. Pulling on the landing gear to relieve the landing gear retaining hook;
e. Actuating the landing gear hook to free the landing gear;
f. Moving the landing gear to bring it from the retracted position to the deployed position, causing the landing gear to be automatically locked when it reaches the deployed position;
g. Closing the doors, causing the retaining hook to be automatically rearmed when the doors reach the closed position.
The manoeuvre of raising a landing gear, for its part, comprises the following successive steps:
a. Pulling on the doors of the bay to relieve the door retaining hook;
b. Actuating the door hook or hooks to free the doors;
c. Opening the doors;
d. Unlocking the landing gear;
e. Moving the landing gear to bring it from the deployed position to the retracted position, causing the landing gear hook to be automatically rearmed when the landing gear reaches the retracted position;
f. Closing the doors, causing the door hook or hooks to be automatically rearmed when the doors reach the closed position.
These steps, which are generally initiated by the pilot actuating a control member (a button, a lever) take a certain time, typically ten to twenty seconds, especially since one must take into account the delay times, detections and confirmation of position, and the logical processing by the control unit which manages these manoeuvres.
There is currently a need to reduce this time, especially the sequence of raising the landing gear. Indeed, landing gear in the deployed position disrupts the airflow around the aircraft, is a source of noise, and forms an obstacle which must be retracted in order to ensure the safety of the aircraft.
A person skilled in the art would first think of increasing the size of the actuators which move the doors and the landing gear, in order to speed up the movement thereof. However, this solution is costly.